London, Nov 2 : Expecting mums will be warned not to drink more than two cups of coffee a day or risk giving birth to underweight babies, according to a health watchdog.
The British Government's food standards watchdog will this week issue the guidance advising women to limit caffeine consumption to 200mg a day, a third less than the previous recommended limit of 300mg.
The warning follows a US study earlier this year that linked caffeine consumption to a higher rate of miscarriages.
The advice from the Food Standards Agency (FSA) comes a week after scientists found that a weekly glass of wine during pregnancy could help improve a baby's behaviour and vocabulary.
It warned women to restrict all products including caffeine, such as cola, energy drinks and chocolate. The limit works out at two cups of instant or brewed coffee, four cups of tea or five cans of cola.
"This is new advice but these are not new risks. I want to reassure women that if you're pregnant and have been following the previous advice, the risk is likely to be tiny," the Scotsman quoted Andrew Wadge, the FSA's chief scientist, as saying.
The watchdog is changing its guidelines following advice from the independent committee on toxicity, which after assessing the new research and previous studies decided that caffeine could be harmful to the unborn child at lower levels.
Boffins from Leicester and Leeds universities monitored the daily caffeine intake of 2,500 pregnant women using questionnaires. They compared this with the birth weight of the baby, taking into account the weight and ethnic background of the mother.
The research will be published in the British Medical Journal.